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IEEE 1584-2018 documents the standard method for calculating arc flash incident energy. This value is then used to establish one of several safety boundaries around exposed, energized electrical conductors and to select protective equipment. While 1584 covers three-phase configurations in detail, it currently excludes single-phase calculations. The prevalence of single-phase ac power distribution inspired curiosity about the possible hazards of fire and injury arising from arc flash in such systems.

ABSTRACT:The author discusses his personal experiences with Nathaniel Branden and Devers Branden, as friends and mentors, which began with a weekend Intensive in 1980 and continued for over thirty-five years. He examines the ways in which these experiences shaped his life, a description of some of the work with “sub-personalities” that Nathaniel and Devers developed together, and the conception of happiness as a discipline.

Cholera, a diarrheal disease, is known for explosive epidemics that can quickly kill thousands. Endemic cholera is a seasonal torment that also has a significant mortality. Not all nations with extensive rural communities can achieve the required infrastructure or behavioral changes to prevent epidemic or endemic cholera. For some communities, a single‐dose cholera vaccine that protects those at risk is the most efficacious means to reduce morbidity and mortality. It is clear that our understanding of what a protective cholera immune response is has not progressed at the rate our understanding of the pathogenesis and molecular biology of cholera infection has. This review addresses V. choleraelipopolysaccharide (LPS)‐based immunogens because LPS is the only immunogen proven to induce protective antibody in humans. We discuss the role of anti‐LPS antibodies in protection from cholera, the importance and the potential role of B cell subsets in protection that is based on their anatomical location and the intrinsic antigen‐receptor specificity of various subsets is introduced.

ABSTRACTVibrio choleraeis a gram-negative bacterium that has been associated with cholera pandemics since the early 1800s. Whole-cell, killed, and live-attenuated oral cholera vaccines are in use. We and others have focused on the development of a subunit cholera vaccine that features standardized epitopes from various V. choleraemacromolecules that are known to induce protective antibody responses. TcpA protein is assembled into toxin-coregulated pilus (TCP), a type IVb pilus required for V. choleraecolonization, and thus is a strong candidate for a cholera subunit vaccine. Polypeptides (24 to 26 amino acids) in TcpA that can induce protective antibody responses have been reported, but further characterization of their amino acid targets relative to tertiary or quaternary TCP structures has not been done. We report a refinement of the TcpA sequences that can induce protective antibody. One sequence, TcpA 15 (residues 170 to 183), induces antibodies that bind linear TcpA in a Western blot as well as weakly bind soluble TcpA in solution. These antibodies bind assembled pili at high density and provide 80 to 100% protection in the infant mouse protection assay. This is in sharp contrast to other anti-TcpA peptide sera (TcpA 11, TcpA 13, and TcpA 17) that bind very strongly in Western blot and solution assays yet do not provide protection or effectively bind TCP, as evidenced by immunoelectron microscopy. The sequences of TcpA 15 that induce protective antibody were localized on a model of assembled TCP. These sequences are centered on a site that is predicted to be important for TCP structure.

ABSTRACTDevelopment of Vibrio choleraelipopolysaccharide (LPS) as a cholera vaccine immunogen is justified by the correlation of vibriocidal anti-LPS response with immunity. Two V. choleraeO1 LPS serotypes, Inaba and Ogawa, are associated with endemic and pandemic cholera. Both serotypes induce protective antibody following infection or vaccination. Structurally, the LPSs that define the serotypes are identical except for the terminal perosamine moiety, which has a methoxyl group at position 2 in Ogawa but a hydroxyl group in Inaba. The terminal sugar of the Ogawa LPS is a protective B-cell epitope. We chemically synthesized the terminal hexasaccharides of V. choleraeserotype Ogawa, which comprises in part the O-specific polysaccharide component of the native LPS, and coupled the oligosaccharide at different molar ratios to bovine serum albumin (BSA). Our initial studies with Ogawa immunogens showed that the conjugates induced protective antibody. We hypothesized that antibodies specific for the terminal sugar of Inaba LPS would also be protective. Neoglycoconjugates were prepared from synthetic Inaba oligosaccharides (disaccharide, tetrasaccharide, and hexasaccharide) and BSA at different levels of substitution. BALB/c mice responded to the Inaba carbohydrate (CHO)-BSA conjugates with levels of serum antibodies of comparable magnitude to those of mice immunized with Ogawa CHO-BSA conjugates, but the Inaba-specific antibodies (immunoglobulin M [IgM] and IgG1) were neither vibriocidal nor protective in the infant mouse cholera model. We hypothesize that the anti-Inaba antibodies induced by the Inaba CHO-BSA conjugates have enough affinity to be screened via enzyme-linked immunosorbent assay but not enough to be protective in vivo.

Toll-like receptors are important in the activation of innate immunity, and CD40 is a molecule critical for many T and B cell responses. Whereas agonists for either pathway have been used as vaccine adjuvants, we show that a combination of Toll-like receptor (TLR)7 and CD40 agonists synergize to stimulate CD8+ T cell responses 10–20-fold greater than the use of either agonist alone. Antigen-specific CD8+ T cells elicited from combination CD40/TLR7 treatment demonstrated both lytic activities and interferon (IFN)γ production and an enhanced secondary response to antigenic challenge. Agonists for TLRs 2/6, 3, 4, and 9 also synergized with CD40 stimulation, demonstrating that synergy with the CD40 pathway is a property of TLR-derived stimuli in general. The CD8+ T cell expansion induced by CD40/TLR7 triggering was independent of CD4+ T cells, IFNγ, and IL-12 but dependent on B7-mediated costimulation and surprisingly on type I IFN. These studies provide the rational basis for the use of TLR and CD40 agonists together as essential adjuvants to optimize vaccines designed to elicit protective or therapeutic immunity.

Toll‐like receptors (TLRs) recognize pathogen‐associated molecular patterns, which are non‐self macromolecular components of pathogens that allow the innate‐immune system to recognize infection. TLRs are expressed on macrophages and dendritic cells (DC). TLR stimulation or CD40 agonists can induce inflammatory cytokine secretion from macrophages and DC, and promote DC maturation. The regulation of TLR expression by inflammation has begun to be explored. Our studies have focused on the regulation of TLR4 surface expression on DC. TLR4, along with the adaptor molecule MD2, is involved in the recognition of lipopolysaccharide (LPS). CD40 stimulation via cross‐linked anti‐CD40 monoclonal antibody (mAb) up‐regulates TLR4‐MD2 surface expression on a DC cell line (DC2.4) and on ex vivo‐cultured splenic DC. LPS treatment down‐regulated surface TLR4‐MD2 on DC2.4 cells, but if combined with anti‐CD40 mAb, increased TLR4‐MD2 expression was observed. The increased TLR4‐MD2 surface expression by any treatment did not correlate with TLR4 mRNA levels. The functional consequence of increased TLR4‐MD2 expression following LPS and anti‐CD40 treatment was examined. Although CD40 prestimulation did slightly enhance interleukin‐12p70 secretion after LPS restimulation, simultaneous anti‐CD40 mAb and LPS treatment, which up‐regulates TLR4‐MD2 complex, does not restore DC responsiveness to subsequent LPS.

Probing a cerebellar expression library with TrAb sera from patients with Hodgkin's disease and paraneoplastic cerebellar degeneration resulted in the isolation of MAZ (myc‐associated zinc‐finger protein). Eleven of 19 TrAb sera and 16 of 131 controls reacted with MAZ, indicating a significant, although not specific, association between Tr and MAZ immunities (p< 0.001). Interestingly, 9 of 16 positive control patients also had cerebellar dysfunction. Purified MAZ antibodies reacted with Purkinje cells. In neuronal cells, MAZ interacts with DCC (Deleted in Colorectal Cancerproduct), the receptor for netrin‐1, a neuronal survival factor. These findings suggest epitope spreading between the Tr antigen and the MAZ–DCC complex and offer a possible model of immune‐mediated cerebellar disease. Ann Neurol 2003;53:000–000

The human IgA Fc receptor (FcαR, CD89) triggers several important physiological functions, including phagocytosis, NADPH oxidase activation and antigen presentation. Efforts are underway to delineate FcαR signal-transduction pathways that control these functions. In a previous study, we demonstrated that cross-linking of FcαR increased its partitioning into membrane glycolipid rafts and was accompanied by γ-chain-dependent recruitment and phosphorylation of the tyrosine kinases Lck/Yes-related novel protein tyrosine kinase (Lyn) and Bruton's tyrosine kinase (Btk). Here we have performed a more extensive characterization of signalling effectors recruited to rafts on FcαR cross-linking. We demonstrate that in addition to tyrosine kinases Lyn and Btk, FcαR cross-linking also recruits B-lymphocyte kinase (Blk) and spleen tyrosine kinase (Syk) to rafts. We show recruitment of phosphoinositide kinases, including 3-phosphoinositide 3-kinase and phospholipase Cγ2, and serine/threonine kinases such as protein kinase C (PKC) α, PKC∊, and protein kinase B (PKB) α. This suggests that lipid rafts serve as sites for FcαR-triggered recruitment of multiple classes of signalling effectors. We further demonstrate that tyrosine kinases and PKCα have a sustained association with rafts, whereas phosphoinositide 3-kinase and its downstream effectors have a transient association with rafts. This is consistent with temporally regulated divergence of FcαR signalling pathways in rafts. Furthermore, we suggest the spatial separation of signalling effectors by transport of phosphoinositide 3-kinase, phosphoinositide-dependent kinase 1, PKBα and PKC∊ to endocytic compartments containing internalized FcαR.

ABSTRACTToxin-coregulated pilus (TCP) is a colonization factor required for cholera infection. It is not a strong immunogen when delivered in the context of whole cells, yet pilus subunits or TcpA derivative synthetic peptides induce protective responses. We examined the efficacy of immunizing mice with TCP conjugated to anti-class II monoclonal antibodies (MAb) with or without the addition of cholera toxin (CT) or anti-CD40 MAb to determine if the serologic response to TcpA could be manipulated. Anti-class II MAb-targeted TCP influenced the anti-TCP peptide serologic response with respect to titer and isotype. Responses to TcpA peptide 4 were induced with class II MAb-targeted TCP and not with nontargeted TCP. Class II MAb-targeting TcpA reduced the response to peptide 6 compared to the nontargeted TCP response. Class II MAb-targeted TcpA, if delivered with CT, enhanced the serologic response to TcpA peptides. The effectiveness of the combination of targeted TCP and CT was reduced if anti-CD40 MAb were included in the primary immunization. These data establish the need to understand the role of TCP presentation in the generation of B-cell epitopes in order to optimize TcpA-based cholera vaccines.

ABSTRACTCholera is an enteric disease caused by Vibrio cholerae.Toxin-coregulated pilus (TCP), a type 4 pilus expressed by V. cholerae, is a cholera virulence factor that is required for host colonization. The TCP polymer is composed of subunits of TcpA pilin. Antibodies directed against TcpA are protective in animal models of cholera. While natural or recombinant forms of TcpA are difficult to purify to homogeneity, it is anticipated that synthesized TcpA peptides might serve as immunogens in a subunit vaccine. We wanted to assess the potential for effects of the immune response (Ir) gene that could complicate a peptide-based vaccine. Using a panel of mice congenic at the H-2locus we tested the immunogenicity of TcpA peptide sequences (peptides 4 to 6) found in the carboxyl termini of both the classical (Cl) and El Tor (ET) biotypes of TCP. Cl peptides have been shown to be immunogenic in CD-1 mice. Our data clearly establish that there are effects of the Ir gene associated with both biotypes of TcpA. These effects are dynamic and dependent on the biotype of TcpA and the haplotypes of the host. In addition to the effects of the classic class II Ir gene, class I (D, L) or nonclassical class I (Qa-2) may also affect immune responses to TcpA peptides. To overcome the effects of the class II Ir gene, multiple TcpA peptides similar to peptides 4, 5, and 6 could be used in a subunit vaccine formulation. Identification of the most protective B-cell epitopes of TcpA within a particular peptide and conjugation to a universal carrier may be the most effective method to eliminate the effects of the class II and class I Ir genes.

ABSTRACTCholera is an acute diarrheal disease that is caused by the gram-negative bacterium Vibrio cholerae. The low efficacy of currently available killed-whole-cell vaccines and the reactinogenicity coupled with potential reversion of live vaccines have thus far precluded widespread vaccination for the control of cholera. Recent studies on the molecular nature of the virulence components that contribute to V. choleraepathogenesis have provided insights into possible approaches for the development of a defined subunit cholera vaccine. Genetic analysis has demonstrated that the toxin-coregulated pilus (TCP) is the major factor that contributes to colonization of the human intestine by V. cholerae. In addition, polyclonal and several monoclonal antibodies directed against TCP have been shown to provide passive immunity to disease in the infant mouse cholera model. In the present study, synthetic peptides corresponding to portions of the C-terminal disulfide region of TcpA pilin were formulated with polymer adjuvants currently in clinical trials and used to actively immunize adult female CD-1 mice. The experimental vaccine formulations elicited high levels of antigen-specific immunoglobulin G (IgG), including a broad spectrum of subclasses (IgG1, IgG2a, IgG2b, and IgG3), and lower levels of IgA. Infant mice born to the immunized mothers showed 100% protection against a 50% lethal dose (1 LD50) challenge and 50% protection against a 10-LD50challenge with virulent strain O395. These results indicate that specific regions of TcpA, including those delineated by the peptides used in this study, have the potential to be incorporated into an effective defined subunit vaccine for cholera.

Antibodies to Ma1 and Ma2 proteins identify a paraneoplastic disorder that affects the limbic system, brain stem, and cerebellum. Preliminary studies suggested the existence of other Ma proteins and different patterns of immune response associated with distinct neurologic symptoms and cancers. In this study, our aim was to isolate the full‐length sequence of Ma2and new family members, identify the major autoantigen of the disorder, and extend the clinical–immunological analysis to 29 patients. Sera from selected patients were used to probe a brainstem cDNA library and isolate the entire Ma2gene and a new family member, Ma3.Ma3 mRNA is ubiquitously expressed in brain, testis, and several systemic tissues. The variable cellular expression of Ma proteins and analysis of protein motifs suggest that these proteins play roles in the biogenesis of mRNA. Immunoblot studies identify Ma2 as the major autoantigen with unique epitopes recognized by all patients' sera. Eighteen patients had antibodies limited to Ma2: they developed limbic, hypothalamic, and brainstem encephalitis, and 78% had germ‐cell tumors of the testis. Eleven patients had antibodies to Ma2 and additional antibodies to Ma1 and/or Ma3; they usually developed additional cerebellar symptoms and more intense brainstem dysfunction, and 82% of these patients had tumors other than germ‐cell neoplasms. Overall, 17 of 24 patients (71%) with brain magnetic resonance imaging studies had abnormalities within or outside the temporal lobes, some as contrast‐enhancing nodular lesions. A remarkable finding of immunity to Ma proteins is that neurologic symptoms may improve or resolve. This improvement segregated to a group of patients with antibodies limited to Ma2.

Inflammatory mediators facilitate the maturation of dendritic cells (DC), enabling them to induce the activation, proliferation and differentiation of cognate T cells. The role of CD40 on DC and CD154 on T cells has been studied by the co-adoptive transfer of antigen-pulsed DC and TCR-transgenic (Tg) T cells in vivo. It is shown that in the absence of CD40-CD154 interactions, initial Tg T cell expansion occurs in vivo, but over time, T cell expansion cannot be sustained. The basis for the demise of the T cell population is likely due to the disappearance of the antigen-pulsed DC in the draining lymph nodes when CD154-CD40 interactions are interrupted. These findings show that both T cell and DC persistence in vivo is dependent on CD40-CD154 interactions. In addition to the physical persistence of the DC, CD40 triggering of DC also greatly increases the period for which they can productively present antigen to Tg T cells. Hence DC persistence and antigen-presenting cell capacity are both dependent on CD40 signaling. While TNF-α can mature DC as measured by a variety of criteria, the unique capacity of CD40 signaling to sustain T cell responses and induce DC maturation is underscored by the inability of TNF-α to rescue the immune deficiency of CD40^–/– DC. Hence, the profound impact of CD154 deficiency on cell-mediated immunity may be due to its ability to limit the duration of antigen presentation in vivo and cause the premature demise of antigen-specific T cells.

The mechanism of enhanced presentation of ovalbumin (OVA) internalized as immunoglobulin A (IgA)–OVA via the IgA Fc receptor (FcαR) was analyzed by focusing on the role of the FcαR-associated γ chain. Comparison of B-cell transfectants expressing FcαR plus wild-type (WT) γ chain or γ chain in which the immunoreceptor tyrosine-based activation motif (ITAM) was altered by tyrosine mutation or substitution with the ITAM of FcγRIIA showed that signaling-competent ITAM was not required for endocytosis of IgA-OVA. However, antigen presentation was impaired by ITAM changes. Signaling-competent γ-chain ITAM appeared necessary for transport of ligated FcαR to a lamp-1+late endocytic compartment for remodeling and/or activation of that compartment and also for efficient degradation of IgA complexes. Moreover, FcαR ligation also activated efficient processing of nonreceptor-targeted antigen. The results suggest that γ-chain signaling activates the antigen processing compartment.

Antigen-presenting cells internalize antigen by fluid-phase pinocytosis or by endocytosis via surface receptors such as the B cell receptor (BCR) and Fc receptors for IgG, IgA and IgE (FcR). While both modes of internalization lead to antigen presentation it is recognized that receptor-mediated endocytosis greatly enhances the efficiency of processing and antigen presentation. Receptors facilitate the entry of antigen into the endocytic pathway by interaction of their internalization motifs with the endocytic machinery. These motifs include tyrosine-based, dileucine and casein kinase-like motifs. However these structures appear insufficient to support processing of cryptic epitopes, leading to a limited immune response. Cryptic epitope processing appears dependent on receptor signaling which is mediated by immunoreceptor tyrosine activation motifs (ITAMs). The signaling cascade which follows receptor crosslinking promotes reorganization and acidification of the late endocytic compartment or MIIC. Signaling events downstream of Syk, in particular calcium flux and protein kinase C activation, are necessary for MIIC induction. PI(3) kinase is also involved at multiple steps in antigen presentation, including production of PIP3 and transport of cathepsins. PIP3 is crucial both as a binding substrate for proteins implicated in vesicle transport and for the recruitment of signaling molecules to the plasma membrane. Among PIP3 activated molecules, protein kinase B (PKB) has been linked to endocytic function. We observe association of activated PKB with the MIIC after signaling through antigen presentation-competent receptors, but not mutant, presentation-defective receptors.

Rotational and lateral diffusion of I-A(k) molecules with various alpha and beta chain cytoplasmic truncations known to affect class II function were measured to assess the role of cytoplasmic domains in regulating I-A(k) molecular motions. Deletion of all 12 alpha chain C-terminal residues and all 18 corresponding beta chain residues (alpha-12/beta-18) is known to abrogate translocation of protein kinase C to the nucleus upon class II cross-linking. Similarly, truncation of the entire cytoplasmic alpha chain domain and the 10 C-terminal residues of the beta chain impairs presentation of antigenic peptides to T cells. The rotational correlation time of the wild-type molecule, 11.9 +/- 2.6 micros as measured by time-resolved phosphorescence anisotropy, decreased to 7. 2 +/- 3.7 micros in the fully truncated alpha-12/beta-18 protein. Other truncated class II molecules exhibited only small changes in molecular rotation rates relative to the wild-type. The rate of lateral diffusion of the fully truncated molecule, measured with two independent methods, 2.3 x 10(-10) cm(2)/s, was comparable with that of the wild-type molecule. Thus, it appears that the alpha and beta chain cytoplasmic domains regulate the molecular motions of unperturbed I-A(k) molecules only modestly, despite the known involvement of these regions in class II signaling. Various explanations for this behavior are discussed, e.g. the possibility that class II membrane complexes are sufficiently large that association and dissociation of specific signaling proteins during antigen presentation do not significantly perturb the apparent molecular motions of the complex.

A previous investigation demonstrated that several mutations in class II dimer-of-dimers contact residues interfere with antigen presentation by transfectants but not with plasma membrane expression of the mutant class II. In the present study we examined other class II mutations in this region that did inhibit plasma membrane expression of mutant class II molecules. Molecules containing both mutations H alpha 181D in the alpha(2) domain and E beta 170K in the beta(2) domain exhibited low plasma membrane expression, but molecules with only one of these mutations were expressed normally. The mutant class II molecules were transported to organelles that were accessible to a fluid-phase protein, hen egg lysozyme (HEL). Culture of transfectants with lysozyme enhanced the amount of class II compact dimer (alpha beta plus peptide; CD), and this was especially marked for the class II mutant H alpha 181D/E beta 170K and for other molecules possessing both mutations. Formation of class II CD was not paralleled by an increase in class II surface expression. Thus the joint mutation of H alpha 181 and E beta 170 has two effects. In the absence o high concentrations of exogenous peptide, it prevents efficient CD formation, possibly by affecting invariant chain (Ii) proteolysis and/or the stability of the class II after Ii/CLIP is removed. At high peptide concentrations supplied by exogenous HEL, the mutations allow CD formation, but not expression of class II on the plasma membrane. Molecular modeling of the possible interaction of class II and Ii suggests that the mutant amino acids H alpha 181D and E beta 170K, besides affecting the overall stability of class II, might also interact with Ii via two loops in class II's alpha(2) and beta(2) domains respectively.

Fluorescence photobleaching recovery (FPR) measurements of cell surface protein lateral diffusion typically employ an interrogated spot of 0.5μm 1/e2 radius. The effective spot area represents only 1/500 of the total surface of an 8-μm cell. An FPR measurement of a protein expressed as 50,000 copies per cell reflects the dynamics of 100molecules. This limits the precision and reproducibility of FPR measurements. We describe a method for interferometric fringe pattern FPR that permits simultaneous interrogation of the entire cell’s surface. Fringe patterns are generated interferometrically within the optical path of an FPR system. Methods for interpreting fluorescence recovery kinetics on cells and for determining the protein mobile fraction are presented. With fringe FPR, the murine major histocompatibility complex class II antigen I-Ak expressed on M12.C3.F6 cells has 100-fold improved fluorescence signals relative to spot FPR, with corresponding improvements in signal-to-noise ratios of recovery traces. Diffusion coefficients (± standard deviation) of (2.1±0.4)×10−10 and (1.8±1.0)×10−10cm2s−1 with corresponding mobile fractions of I-Ak of 66.1±7.8% and 63.4±18.0% were obtained by fringe and spot methods, respectively. The improved reproducibility of fringe over spot results is less than signal improvements predict. There may thus be substantial variation from cell to cell in protein dynamics, and this method may permit the assessment of such variation.

While some of the gaseous and paniculate components ofdiesel exhaust can cause pulmonary irritation and bronchial hyperreactivity, diesel exhaust exposure has not been shown to cause asthma. Three railroad workers developed asthma following excessive exposure to locomotive emissions while riding immediately behind the lead engines of caboose-less trains. Asthma diagnosis was based on symptoms, pulmonary function tests, and measurement of airways hyperreactivity to methacholine or exercise. One individual's peak expiratory flow rates fell in a work-related pattern when riding immediately behind the lead diesel engine. None had a previous history of asthma or other respiratory disease and none were current smokers. All three developed persistent asthma. In two cases, physiologic abnormalities suggesting reversible restriction were observed. This is the first report implicating diesel exhaust as a cause of reactive airways disease.

A Remote High Dose Rate (HDR) Brachytherapy Iridium-192 System for outpatient brachytherapy procedures necessitates a variety of applicators in order to accomplish the optimal desired treatment for the patient’s tumor involved anatomy. The Nucletron Corporation that manufactures the microselection HDR Iridium-192 treatment unit provided us with their standard applicators; however, a rectal applicator system was not available at the time of purchase. In order to provide this treatment to the patient, the physicians and the physicists designed a custom set of rectal applicators that would meet the current and immediate needs of our patients. A description of the clinical rationale and physical aspects of the rectal applicator system, including design and radiation dosimetry will be presented.

Neuropeptide Y (NPY) has been shown to increase gonadotropin secretion directly at the level of the anterior pituitary (AP) in both the absence and the presence of luteinizing hormone-releasing hormone (LHRH). This is interesting because highaffinity 125I-NPY-binding sites have not been found in the AP. However, high-affinity 125I-NPY-binding sites have been localized in the posterior pituitary (PP), and it has been shown that removal of the PP alters luteinizing hormone (LH) secretion in vivo.The following studies were conducted to determine if gonadotropin responsiveness to either NPY alone or to NPY in combination with LHRH was significantly different in AP cells cultured in the presence compared with the absence of PP cells. The studies indicated that NPY-induced LH secretion was significantly greater in the presence of PP cells, while follicle-stimulating hormone (FSH) secretion was not significantly affected. LHRH-induced LH secretion was also significantly greater in the presence of PP cells; however, LHRH-induced FSH secretion was significantly decreased. NPY potentiated LHRH-induced LH secretion in AP cells cultured in both the presence and the absence of PP cells; however, the degree of potentiation was not significantly different whether PP cells were present or absent. These results indicate that the PP may play a role in the responsiveness of the AP to NPY and to LHRH but plays no apparent role in NPY potentiation of LHRH responsiveness.

A North Carolina study revealed that certain pesticides have impacted groundwater above health‐based standards in vulnerable areas. Ninety‐seven shallow, surficial aquifer‐monitoring wells were sampled at least twice. Sites for the monitoring wells were chosen based on an evaluation with the Pesticide DRASTIC model and a known record of pesticide use. Where possible, areas of greater risk were intentionally selected. Twenty‐three pesticides or pesticide degradates were detected in 26 of the 97 wells. Nine of the pesticides or degradates are no longer registered for use; two of these chemicals, dibromochloropropane and methylene chloride, were found in excess of health‐based guidance levels (HBGL) or state groundwater quality standards (GWQS). Of the registered pesticides or their degradates, the herbicides dichlorprop and simazine and the insecticide isomers BHC‐alpha and BHC‐delta were in excess of HBGL. The herbicide atrazine was detected at 83% of its GWQS. The U.S. Environmental Protection Agency (USEPA) Pesticides and Groundwater State Management Plans will be required for atrazine and simazine to be sold and used, which will provide additional protection to public health and the environment. Pesticide DRASTIC ratings or soil‐leaching potential values and the proportion of wells were unrelated to pesticide detections.

Data accumulated to date from the Los Angeles study indicate that the total termination rate for 12 months from the beginning of the training period and from formal entry into the study was high for the ovulation method (OM), and symptothermal method (STM). Voluntary withdrawal was the highest single reason for termination in both methods. The 12 month voluntary withdrawal rate, measured from formal entry into the study, was significantly for OM users. Pregnancy rates measured from both the beginning of training and formal entry into the study were significantly higher for OM users than for STM users. Complete analysis of the data colleccted during the study is currently in progress. It is anticipated that some of the causes for the differences in pregnancy rates and withdrawal rates between the two methods can be identified.